I know TCP segments are numbered (with sequence numbers) for reassembly/error recovery reasons.
How do TCP segments and IP fragmentation correlate? If the sender has an IP datagram that exceeds the layer 2's MTU, it fragments the datagrams and each datagram gets sent as separate frames across the wire.
Now, what is responsible for reassembly on the other end? I know that with packet fragmentation, a packet id is defined and the "fragment" flag is turned on. What is TCP's job in the reassembly of fragged IP datagrams? Arent the fragmented packets ID'd anyway?